1. Field of the Invention
The invention is directed to lateral seal for sieve devices with a grate having a plurality of grate bars which are alternately movable and immovable with respect to the side walls and which are connected by flexible sieve elements which are fastened to the grate bars and bridge the gaps between the grate bars and which are moved or tensioned and relaxed by the movable grate bars, wherein the lateral seal formed of flexible material is connected in a stationary manner with the sieve elements on the one hand and with side frame parts on the other hand.
2. Description of the Related Art
A lateral seal of this type is known, for instance, from AT-B-386 969 by the present applicant. In order to improve the sealing action, it is proposed that the lateral seal be formed of a series of sealing leaves overlapping one another in an imbricated manner, this overlapping preventing unwanted leakage of the sieved material.
There is also a completely different type of sieve seal for such sieve devices which is described, e.g., in DE-A1-28 13 630, which uses a resilient sealing body. This sealing body bridges the gap between the side wall and the sieve lining and is formed of a resilient foam plastic. Since such seals are subject to intensive wear in heavy-duty operation, in particular in the region of the grate bars which are movable relative to the side wall, it has been suggested in EP-B 0 206 164 to improve the life of these seals by constructing the sealing body from individual members of varying length, wherein, in the region of the movable grate bars, a short member is directly connected with the grate bar in each instance by means of a holder and the distance between these short members, which substantially corresponds to the distance between adjacent grate bars which are movable relative to the side wall, is bridged by a continuous longer member.
The present invention is directed to lateral seals of the type mentioned above which are formed of sealing leaves overlapping one another in an imbricated manner, wherein it is provided, according to the invention, to improve the sealing characteristics in that every sealing leaf, as viewed in the sieving direction, extends between two grate bars which are stationary relative to the side wall. The grate bars in question are preferably adjacent stationary grate bars so that only one movable grate bar is located between them.
As a result of the steps according to the invention, the starting end and terminating end of the sealing leaf are immovable relative to the side wall. Accordingly, on the one hand, two adjacent sealing leaves can abut simply by means of imbricated overlapping and on the other hand tightness is improved
Further, the life of the lateral seal is substantially increased, since the mechanical fastening which is naturally exposed to the greatest stress at the edges is likewise arranged so as to be immovable so that localized dynamic loading is practically eliminated.
The movements produced by the movable grate bar approximately in the center of every sealing leaf can be distributed in a substantially improved manner by the leaf which is homogeneous at this location and can accordingly be withstood over a longer period of time than if such forces were introduced at the edges of the sealing leaf.
The invention is explained more fully with reference to the accompanying drawings.